Air-cooling garments are used by military and civilian agencies for protection of personnel against heat stress. These air-cooling garments are worn during normal operations and provide cooling by delivering cool, dry air over the body (primarily the torso). Cooling is achieved by increasing conduction, convection, and the rate of evaporation of sweat.
These garments remove the greatest amount of heat when the skin and underclothing beneath the air-cooling garment are saturated with sweat. Sweating the body's natural cooling mechanism occurs when the subject is overheated and may either nearing or be suffering from heat stress. Therefore, air-cooling garments tend to function most effectively when the subject is already on the way towards becoming heat stressed. Even mild heat stress is known to reduce both comfort and hence degrades wearer's cognitive and physical performance. Extreme heat stress can lead to unconsciousness and/or death.
The concepts of air cooling garments appear in the patent literature, for example, in Canadian Patent No. 2,051,358.